LU500928B1

LU500928B1 - Coil assembly of current transformer and method for producing the same

Info

Publication number: LU500928B1
Application number: LU500928A
Authority: LU
Inventors: Siyu Song; Weidong Wang; Xiaofeng Huang; Wei Zhang; Weiwei Huang; Bin Lin; Haoda Wu; Yunfeng Chang
Original assignee: Denggao Electric Co Ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-05-30

Abstract

A coil assembly of a current transformer, including two superimposed coil windings, wherein the coil winding includes a main annular iron core, a first insulation layer wrapped on the main annular iron core, a coil wound on the first insulation layer, a compensation annular iron core provided inside the coil, a second insulation layer wrapped on the compensation annular iron core, and a third insulation layer wrapped on the coil; a sponge layer is wrapped on the two coil windings, and a fourth insulation layer is wrapped on the sponge layer; incoming leads of the two coil windings are connected and form an incoming end, and outgoing leads of the two coil windings are connected and form an outgoing end; the incoming end and outgoing end respectively pass through the sponge layer and the fourth insulation layer and are exposed outside the fourth insulation layer; the incoming end and outgoing end are correspondingly provided with an incoming copper insert and an outgoing copper insert. The disclosure has advantages of a simple structure, stable and reliable performance, low production costs, and high yield.

Description

COIL ASSEMBLY OF CURRENT TRANSFORMER AND METHOD FOR LUS00928

PRODUCING THE SAME TECHNICAL FIELD

[01] The disclosure relates to a current transformer, more particularly, to a coil assembly of a current transformer and a method for producing the same.

BACKGROUND ART

[02] A current transformer is an instrument that converts a large current on the primary side into a small current on the secondary side for measurement under the law of electromagnetic induction and consists of a closed core and windings. The current transformer includes a transformer body and a coil assembly provided inside the transformer body. The conventional coil assembly of the current transformer has an unreasonable design, which requires a complicated production process and intensive labor, and features a poor production efficiency and low acceptability, i.e., about 60%, of the low transformation ratio the current transformer with such a design. Such low acceptability of the product leads to an inflated cost and a low yield in the production of the current transformer.

SUMMARY

[03] It is an object of the disclosure to eliminate the defects in the prior art by providing a coil assembly of a current transformer having a simple structure, stable and reliable performance, and low production costs.

[04] To achieve the above object, the disclosure adopts a coil assembly of a current transformer, including two superimposed coil windings, wherein the coil winding includes a main annular iron core, a first insulation layer wrapped on the main annular iron core, a coil wound on the first insulation layer, a compensation annular iron core provided inside the coil, a second insulation layer wrapped on the compensation annular iron core, and a third insulation layer wrapped on the coil; a sponge layer is wrapped on the two coil windings, and a fourth insulation layer is wrapped on the sponge layer; incoming leads of the two coil windings are connected and form an incoming end, and outgoing leads of the two coil windings are connected and form an outgoing end; the incoming end and outgoing end respectively pass through the sponge layer and the fourth insulation layer and are exposed outside the fourth insulation layer; the incoming end and outgoing end are correspondingly provided with an incoming copper insert and an outgoing copper insert.

[05] In particular, a ceramic capacitor is connected between the incoming and outgoing ends. The acceptability of the coil assembly can be increased to 80%-90% by the advantage of ceramic capacitor compensation to improve the coincidence of full load and light load.

[06] In particular, the first insulation layer, the second insulation layer, the third insulation layer, and the fourth insulation layer are all insulating crepe paper. The insulating crepe paper has the advantages of anti-static property and good insulating performance, which can effectively secure the operation of the current transformer and 1 prevent the short circuit or disconnection caused by conduction, thereby effectively LU500928 reducing the failure rate and improving the stability of the current transformer.

[07] A method for producing the coil assembly of the current transformer described above, characterized by including the steps of:

[08] (1) testing a main iron core: selecting two main annular iron cores according to a requirement for performance of the current transformer, testing each main annular iron core with an iron core tester, and keeping the main annular iron core meeting the requirement for subsequent use;

[09] (2) wrapping the main iron core: wrapping the two main annular iron cores obtained in step (1) respectively by winding one turn along an edge of the main annular iron core with a PVC adhesive tape and then winding two layers of the crepe paper;

[10] (3) coiling: selecting 10 enameled wires with a diameter of 0.38 mm and 5 enameled wires with a diameter of 0.25 mm, winding 30 turns on the two main annular iron cores obtained in step (2), respectively, with the selected 15 enameled wires, and reserving a margin length of 50 mm at two ends of the enameled wire as an incoming lead and an outgoing lead;

[11] (4) preparing a compensating core: withdrawing five turns of the two coils obtained in step (3), respectively, measuring a peripheral size of the coil after withdrawing the five turns, winding three turns of a twill silicon steel sheet with a thickness of 0.23 mm according to the measured peripheral size of the coil to form two compensating annular iron cores, winding one turn on the two compensating annular iron cores with the PVC adhesive tape, wrapping one turn with the crepe paper, sheathing the wrapped two compensating annular iron cores into the two coils with the five turns withdrawn, winding the withdrawn five turns on the compensating annular iron cores, winding one turn with the PVC adhesive tape, and winding one layer of the crepe paper;

[12] (5) connecting two coils in parallel: overlapping the two coils obtained in step (4), welding the incoming leads of the two coils to form the incoming end, welding the incoming copper insert onto the incoming end, welding the outgoing leads of the two coils to form the outgoing end, welding the outgoing copper insert onto the outgoing end, selecting a 10uF ceramic capacitor, and welding two ends of the ceramic capacitor onto the incoming end and the outgoing end, respectively, so that a coil assembly is obtained;

[13] (6) testing the coil assembly: bringing the coil assembly obtained in step (5) into a P1 end and a P2 end of a tester to check errors, and keeping the coil assembly for subsequent use if the coil assembly passes the test; and

[14] (7) wrapping the coil assembly: selecting a sponge with a thickness of 3 mm, winding one turn around the coil assembly obtained in step (6) with the sponge, winding one turn of the PVC adhesive tape for fixing, and wrapping one layer of a self-adhesive insulating crepe paper to complete the manufacture of the coil assembly of the current transformer.

[15] The disclosure is advantageous in that an improvement based on the conventional structure of the coil assembly of the current transformer is made to replace the conventional single iron core structure with a double iron core parallel structure, the 2 double iron core structure provides additional turns of the coil and reduces the leakage LU500928 reactance, and the double iron core structure is provided with a compensating ring iron core for compensation, which is conducive to render a better light load error curve, so the coil assembly of the current transformer has the advantages of a simple structure, stable and reliable performance, and high acceptability that can reach 80%-90%.

BRIEF DESCRIPTION OF THE DRAWINGS

[16] FIG. 1 is a cross-sectional view of an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[17] As shown in FIG. 1, the embodiment of the disclosure is a coil assembly of a current transformer, including two superimposed coil windings 10, wherein the coil winding 10 includes a main annular iron core 11, a first insulation layer 12 wrapped on the main annular iron core 11, a coil 13 wound on the first insulation layer 12, a compensation annular iron core 14 provided inside the coil 13, a second insulation layer wrapped on the compensation annular iron core 14, and a third insulation layer 16 wrapped on the coil 13; a sponge layer 17 is wrapped on the two coil windings 10, and a fourth insulation layer 18 is wrapped on the sponge layer 17; incoming leads 101 of the two coil windings 10 are connected and form an incoming end 102, and outgoing leads 103 of the two coil windings 10 are connected and form an outgoing end 104; the incoming end 102 and outgoing end 104 respectively pass through the sponge layer 17 and the fourth insulation layer 18 and are exposed outside the fourth insulation layer 18; the incoming end 102 and outgoing end 104 are correspondingly provided with an incoming copper insert 105 and an outgoing copper insert 106. A ceramic capacitor 19 is connected between the incoming and outgoing ends 102, 104. The acceptability of the coil assembly can be increased to 80%-90% by the advantage of ceramic capacitor compensation to improve the coincidence of full load and light load. The first insulation layer 12, the second insulation layer 15, the third insulation layer 16, and the fourth insulation layer 18 are all insulating crepe paper. The insulating crepe paper has the advantages of anti-static property and good insulating performance, which can effectively secure the operation of the current transformer and prevent the short circuit or disconnection caused by conduction, thereby effectively reducing the failure rate and improving the stability of the current transformer.

[18] A method for producing the coil assembly of the current transformer described above, characterized by including the steps of:

[19] (1) testing a main iron core: selecting two main annular iron cores according to a requirement for performance of the current transformer, testing each main annular iron core with an iron core tester, and keeping the main annular iron core meeting the requirement for subsequent use;

[20] (2) wrapping the main iron core: wrapping the two main annular iron cores obtained in step (1) respectively by winding one turn along an edge of the main annular iron core with a PVC adhesive tape and then winding two layers of the crepe paper;

[21] (3) coiling: selecting 10 enameled wires with a diameter of 0.38 mm and 5 enameled wires with a diameter of 0.25 mm, winding 30 turns on the two main annular 3 iron cores obtained in step (2), respectively, with the selected 15 enameled wires, and LU500928 reserving a margin length of 50 mm at two ends of the enameled wire as an incoming lead and an outgoing lead;

[22] (4) preparing a compensating core: withdrawing five turns of the two coils obtained in step (3), respectively, measuring a peripheral size of the coil after withdrawing the five turns, winding three turns of a twill silicon steel sheet with a thickness of 0.23 mm according to the measured peripheral size of the coil to form two compensating annular iron cores, winding one turn on the two compensating annular iron cores with the PVC adhesive tape, wrapping one turn with the crepe paper, sheathing the wrapped two compensating annular iron cores into the two coils with the five turns withdrawn, winding the withdrawn five turns on the compensating annular iron cores, winding one turn with the PVC adhesive tape, and winding one layer of the crepe paper;

[23] (5) connecting two coils in parallel: overlapping the two coils obtained in step (4), welding the incoming leads of the two coils to form the incoming end, welding the incoming copper insert onto the incoming end, welding the outgoing leads of the two coils to form the outgoing end, welding the outgoing copper insert onto the outgoing end, selecting a 10uF ceramic capacitor, and welding two ends of the ceramic capacitor onto the incoming end and the outgoing end, respectively, so that a coil assembly is obtained;

[24] (6) testing the coil assembly: bringing the coil assembly obtained in step (5) into a P1 end and a P2 end of a tester to check errors, and keeping the coil assembly for subsequent use if the coil assembly passes the test; and

[25] (7) wrapping the coil assembly: selecting a sponge with a thickness of 3 mm, winding one turn around the coil assembly obtained in step (6) with the sponge, winding one turn of the PVC adhesive tape for fixing, and wrapping one layer of a self-adhesive insulating crepe paper to complete the manufacture of the coil assembly of the current transformer.

[26] An improvement based on the conventional structure of the coil assembly of the current transformer 1s made to replace the conventional single iron core structure with a double iron core parallel structure, the double iron core structure provides additional turns of the coil and reduces the leakage reactance, and the double iron core structure is provided with a compensating ring iron core for compensation, which is conducive to render a better light load error curve, so the coil assembly of the current transformer has the advantages of a simple structure, stable and reliable performance, and high acceptability that can reach 80%-90%.

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Claims

WHAT IS CLAIMED IS: LUS00928

1. A coil assembly of a current transformer, characterized by comprising two superimposed coil windings, wherein the coil winding includes a main annular iron core, a first insulation layer wrapped on the main annular iron core, a coil wound on the first insulation layer, a compensation annular iron core provided inside the coil, a second insulation layer wrapped on the compensation annular iron core, and a third insulation layer wrapped on the coil; a sponge layer is wrapped on the two coil windings, and a fourth insulation layer is wrapped on the sponge layer; incoming leads of the two coil windings are connected and form an incoming end, and outgoing leads of the two coil windings are connected and form an outgoing end; the incoming end and outgoing end respectively pass through the sponge layer and the fourth insulation layer and are exposed outside the fourth insulation layer; the incoming end and outgoing end are correspondingly provided with an incoming copper insert and an outgoing copper insert.

2. The coil assembly of a current transformer according to claim 1, characterized in that a ceramic capacitor is connected between the incoming and outgoing ends.

3. The coil assembly of a current transformer according to claim 1 or 2, characterized in that the first insulation layer, the second insulation layer, the third insulation layer, and the fourth insulation layer are all insulating crepe paper.

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